A mineral is

Minerals
A mineral is an element or chemical compound 
A mineral is normally crystalline 
A mineral can be defined as a naturally occurring inorganic solid ,it has been formed as a result of geological processes and a definite chemical composition. Some people, like physicists, might be guilty of picking up a rock and calling it a mineral. The term "rock" is less specific, referring to any solid mass of mineral or mineral-like material. Common rocks are often made up of crystals of several kinds of minerals. There are some substances, like opal, which have the appearance of a mineral but lack any definite internal structure, are sometimes called "mineraloids". Lutgens and Tarbuck give the following list of essential characteristics of a "mineral":

It must occur naturally.
It must be inorganic
It must be a solid
It must possess an orderly internal structure, that is, its atoms must be arranged in a definite pattern.
It must have a definite chemical composition that may vary within specified limits."
The most common minerals are the silicates, as one would guess by looking at the abundances of the elements in the Earth's crust, but there is a great variety of minerals. Minerals are classified in many ways, including hardness, optical properties, crystal structure, etc. Shipman, et al. comment that over 2000 minerals have been found in the Earth's crust, but that about 20 of them are common and fewer than 10 account for over 90% of the crust by mass.

Non-silicates constitute less than 10% of the Earth's crust. The most common non-silicates are the carbonates, the oxides, and the sulfides. There are also naturally occuring phosphates and salts. There are a few elements which occur in pure form, including gold, silver, copper, bismuth, arsenic, lead and tellurium. Carbon is found in both graphite and diamond form. Some minerals are valued as gems because of their hardness, color and beauty.

List of names of metals

List of names all metals

A
Aluminum.Antimony.Arsenic

B
Barium.Beryllium.Bismuth.Boron.bronze.

C
Cadmium.Cesium.Chromium.Cobalt.Copper.

G
Gallium.Germanium.Gold.

H
Hafnium.

I
Indium.Iridium.Iron.Lead.Lithium

M
Magnesium.Manganese.Mercury.Molybdenum.

N
Nickel.


O
Osmium.

P
Platinum.Palladium.

R
Rhodium.Ruthenium.Rhenium.Rubidium.

S
Scandium.Selenium.Silver.Strontium.

T
Tantalum.Tellurium.Thallium.Thorium.Tin.Titanium.Tungsten.

U
Uranium.Vanadium.

Z
Zinc.Zirconium

Top Types Of Metal Used

Five Primary Metal Types

Aluminum

More than 3 billion pounds of aluminum is used annually in U.S. construction, and much of that is in aluminum roof construction and wall systems of commercial buildings. Aluminum is highly receptive to today’s high-performance, architectural coatings. A wide variety of factory-applied coatings and colors perform well and stay colorfast on aluminum roofs, which is critical for highly visible steep-slope roof applications. The coatings also help ensure virtually maintenance-free performance and long service life.

Copper

Long life and low maintenance are critically important qualities for exterior treatments of commercial buildings. Metal is emerging as the material of choice in many roof and wall applications, and copper is proving the most popular among metal types. A primary reason for this is its permanency. Copper roofs can last decades, if not centuries. The oldest copper roof in the United States was installed on the Olde Christ Church in Philadelphia in 1742. In Europe, the copper cornice around the dome at the Pantheon in Rome lasted more than 1,800 years.

Steel

Steel is considered a universal building product because of its strength, versatility, durability, and economic value. Today, standing-seam metal roofs are used for countless structures, including shopping centers, schools, churches, and libraries. According to the American Iron and Steel Institute, steel roof construction is used in nearly half of all low-rise commercial, industrial, and institutional buildings erected in the past several years.

Terne

Terne is produced by coating metals such as carbon steel and stainless steel with a specially formulated alloy containing zinc and tin to dramatically increase corrosion resistance. When terne roofs were first used in colonial times, it contained roughly 80% lead and 20% tin. However, in the latter half of the 20th century, as lead was found to have potentially detrimental effects on health, the lead/tin alloy was replaced. In the mid-1990s, a new and superior zinc/tin alloy was produced that provides improved performance and aesthetics over the original—minus the health risks.

Zinc

Building owners and architects are increasingly turning to zinc roof construction for its long, maintenance-free life and adaptability to various design styles ranging from traditional to modern. Zinc is a natural material that never fades and retains its look over its entire life span. It is also a noncorrosive, environmentally friendly product with a 100%-clear water runoff. Zinc's anticorrosion qualities have led its use extensively as a protective coating for steel and other metals.

Extraction of Gold

Gold mining from alluvium ores was once achieved by techniques associated with placer mining such as simple gold panning and sluicing, resulting in direct recovery of small gold nuggets and flakes. Placer mining techniques since the mid to late 20th century have generally only been the practice of artisan miners. Hydraulic mining was used widely in the Californian gold rush, and involved breaking down alluvial deposits with high-pressure jets of water. Hard rock ores have formed the basis of the majority of commercial gold recovery operations since the middle of the 20th century where open pit and or sub-surface mining techniques are used.

Once the ore is mined it can be treated as a whole ore using a dump leaching or heap leaching processes. This is typical of low-grade, oxide deposits. Normally, the ore is crushed and agglomerated prior to heap leaching. High grade ores and ores resistant to cyanide leaching at coarse particle sizes, require further processing in order to recover the gold values. The processing techniques can include grinding, concentration, roasting, and pressure oxidation prior to cyanidation.


Removing the gold-bearing rock from the ground is just the first step. To isolate pure gold, mining companies use a complex extraction process. The first step in this process is breaking down large chunks of rock into smaller pieces. At a mill, large machines known as crushers reduce the ore to pieces no larger than road gravel. The gravel-like material then enters rotating drums filled with steel balls. In these drums, the ore is ground to a fine slurry or powder.
Next, mill operators thicken the slurry with water to form pulp and run the pulp through a series of leaching tanks. Leaching dissolves the gold out of the ore using a chemical solvent. The most common solvent is cyanide, which must be combined with oxygen in a process known as carbon-in-pulp. As the cyanide and oxygen react chemically, gold in the pulp dissolves. When workers introduce small carbon grains to the tank, the gold adheres to the carbon. Filtering the pulp through screens separates the gold-bearing carbon.
The carbon moves to a stripping vessel where a hot caustic solution separates the gold from the carbon. Another set of screens filters out the carbon grains, which can be recycled for future processing. Finally, the gold-bearing solution is ready for electrowinning, which recovers the gold from the leaching chemicals. In electrowinning, operators pour the gold-bearing solution into a special container known as a cell. Positive and negative terminals in the cell deliver a strong electric current to the solution. This causes gold to collect on the negative terminals.
Smelting, which results in nearly pure gold, involves melting the negative terminals in a furnace at about 2,100 degrees F (1,149 degrees C). When workers add a chemical mixture known as flux to the molten material, the gold separates from the metal used to make the terminals. Workers pour off the flux and then the gold. Molds are used to transform the liquid gold into solid bars called doré bars. These low-purity bars are then sent to refineries all over the world for further processing.
WORLD GOLD PRODUCTION
Major gold-producing countries include South Africa, the United States, Australia, Mexico, Peru, Canada, China, India and Russia. South Africa is the leading gold-producing country, followed by the United States and Australia. In the United States, Nevada is the leading gold producer.

Rare Earth Metals Extraction

RDA Red Mud's got Titanium and Iron by-products - All You Need is Kill the Scrap Metal Industry and Agriculture benefits in The Place Beyond the Pines


“There will be no Mining operations and related pressures on the environment”

Comments by Chairman of the JBI (Jamaica Bauxite Institute), Dr. Parris Lyew-Ayee, at the Ground breaking Ceremony for Nippon Light Metal Company Limited Extraction Plant

After the announcement by Minister of Science, Technology Energy and Mining Phillip Paulwell of Jamaica’s intention to extract Rare Earth Metals from Red Mud located in the RDA (Residue Disposal Area) as originally reported in my blog article entitled “Japan’s Nippon Light Metal Company Limited to mine Rare Earth elements in Jamaica - Jack Reacher recycling gadgets for Rare Earth Elements”, the progress has been relatively brisk.

Please take note of the Word “extraction”…..it’ll pop up later in my article!

This is surprisingly fast for a Government traditionally known for dragging its feet on FDI (Foreign Direct Investment) matters! Minister Phillip Paulwell and Prime Minister Portia Simpson Miller participated in ground breaking exercise for the Extraction of Rare Earth Metals on Monday February 4th 2013.

The Ground breaking Ceremony took with Japanese officials from Nippon Light Metal Company Limited as reported in “Ground broken for Rare-Earth Project”, published Tuesday, February 05, 2013 | 8:23 AM, The Jamaica Observer and “Jamaica breaks ground on rare-earth project”, published February 4, 2013 by David Mcfadden, PhysOrg.

Again note that this is a Rare Earth Extraction Plant, not Mining. The Rare Earth Metals are already in colloidal suspension in the Red Mud Residue at concentration levels 2500 time higher on average than normally found in Red Mud in RDA for other Bauxite Mining operations worldwide as noted in “Up to 2,500 per cent higher concentration levels in Ja’s red Mud 'God-blessed dirt'”, published Wednesday, February 13, 2013 BY JULIAN RICHARDSON Assistant business co-ordinator, The Jamaica Observer.

Precipitation via the addition of a Chemical Binding Agent to react with and make an organo-metallic complex with the Rare Earth Metal. This then settles out of solution and then the Spent Liquor is decanted and recycled back into the process. The remaining residue at the bottom of the Precipitation Tanks is the Green Liquor, and is the first stage of Extraction.

Centrifuging is then used to separate the different Rare Earth Metals via Mass and then the Separate Mixtures either oxidized by a strong oxidizing agent to again precipitate out as an Oxide. This allows the Chemical Binding Agent to be recycled (especially if it’s very expensive in the Process) or Calcination to basically oxidize the Rare Earth to a Oxide, the usual form Rare Earths are sold. Milling and grading to produce powders of various particle size as per requirement by clients is the last stage; presentation is key in selling these toxic Rare Earth Metals.

As such, the Process as suggested above present no direct Mining impact on the environment as, say, Gold Mining would. NEPA (National Environment and Planning Agency) approval further proves this as noted in “NEPA gives OK to rare earth minerals application”, published Thursday January 24, 2013 | 10:10, The Jamaica Gleaner, as ironically this Rare Earth Extraction is a further Recycling of the Red Mud that’s gathering space at the back of Bauxite companies and using up Land that would have other Productive uses.





In an interview with the Jamaica Information Service a few days later as noted in “Red Mud Project No Danger to Environment”, published Monday, 11 February 2013 16:52 by Alecia Smith-Edwards, Jamaica Information Service, Dr. Parris Lyew-Ayee, Chairman of the JBI (Jamaica Bauxite Institute) gives a better answer as it relates to handling of the Bauxite Waste.

His explanation goes into a bit more detail on how safe the Rare Earth Extraction is from Red Mud located in the RDA, quote: “This red Mud will be neutralized with acid, that’s the first thing we do. The red Mud that we have in our various Mud containment ponds…are very safe and secure. It’s caustic (and) alkaline and some people would classify it as a hazardous material. This process is going to neutralize it so it would then be non-toxic. We will then be extracting the rare earth elements, Oxides, from this red Mud”.

Doesn’t get any more straightforward than that!

Public consultations aren’t necessary either as concluded in “No public consultation on rare minerals pilot plant construction”, published Sunday February 10, 2013 6:12 pm, The Jamaica Gleaner. The Rare Earth Extraction will make the problem of having a RDA disappear over time as the Extraction process picks up steam. So it’s already going to be a benefit to the people who have had to tolerate the Caustic Soda (NaOH) smell from the RDA for years.

Added to that the fact that it’s the right type of FDI income generating activity needed for Jamaica post-NDX (National Debt Exchange) as described in my blog article entitled “Jamaican Government to implement NDX, essentially JDX2 2.0 to get IMF Agreement - Tax Reform and FDI Investments Bullet to the Head and Oblivion”, and the GOJ’s “youthful exuberance” over this project is explainable.

But the Good News of Metal Extractions (notice the word again!!) apparently doesn’t stop there.

Turns out after the Rare Earth have been extracted, there may also be Titanium and Iron, also in considerably high concentration, left behind in the waste of Tailings that can also be further extracted. Titanium Oxide and Iron Oxide, both oxides of Transition Metals, may be further by-products that can be extracted from the Red Mud located in the RDA (Residue Disposal Area) as stated in the article “Jamaica hopes to harvest titanium from red Mud”, published Wednesday February 13, 2013, The Jamaica Gleaner.

Even more interesting, a tested, tried and proven method exists to resuscitate mined out Bauxite lands.

This method of Land resuscitation for Agricultural usage involves using Gypsum, chemical name calcium sulfate di-hydrate [CaSO4•2(H2O)] and dried Organic Waste from Farming or just simply Compost mixed into topsoil of mined-out Bauxite Lands as stated in the article “NCU scientist points to recognised solution for alumina dumps”, published Monday, February 11, 2013 BY RHOMA TOMLINSON Observer writer, The Jamaica Gleaner.

If this method of Bauxite Land Resuscitation which was developed by NCU (Northern Caribbean University) Dr. Mark Harris is applied wholesale, it would close the loop as it relates to the effect of Bauxite Mining on Jamaica. This as it would allow former mined out lands to be returned to Agricultural productivity, effectively a recycling even the very land used for Bauxite Mining.

Thus the fears of Opposition Finance spokesperson Audley Shaw are unfounded as noted in “Shaw concerned about environmental impact of rare earth project”, published Wednesday February 20, 2013 7:34 am, RJR News Online. No Mining is involved, merely extraction, with the waste products post-extraction of Rare Earth Metals being further recyclable for Titanium and Iron. And as an additional plus, and the land being further resuscitated via an already approved method being used by the JBI and developed, ironically, by the NCU from Manchester.

These are big revelations being made even as construction for the plant gets underway. Farming stands to benefit in The Place Beyond the Pines (2013). Even better, it’s now a strong incentive to shut down the Scrap Metal Trade as All You Need is Kill (2013) via Rare Earth Metal Mining, as there’s more Iron and Titanium in the Red Mud than currently legally available lying around to be picked up in Jamaica.

rare-earth metals extraction business for downtown plant

 “I hope that City Council, acting as the Utilities Board, will obtain outside, expert counsel in considering this proposal.”
A company that has been battling to save the Martin Drake Power Plant and it’s coal-cleaning Neustream technology that’s used there, says its newest venture could amount to 250 high-tech jobs, $400 million in construction projects and $150 million in sales.

Neumann created NeuMetals earlier this year, with the goal of extracting rare earth metals from fly ash, the leftover product from coal-fired power plants. The technology is similar to that of the NeuStream, which is in jeopardy if the Drake plant is closed as the result of a study due in mid-2013.

Neumann has filed three patents for the NeuMetals process, which he says has the additional benefit of using carbon dioxide from the power plants to extract the metals. The 14 metals that can be extracted include neodymium, europium and yttrium, all critical elements to high-tech companies.

“We’ve had great success extracting the metals from the fly ash,” he said. “Overall, we can remove about 60 percent of the metals, some of them we can remove 100 percent.”

The big payoff won’t come immediately. Neumann plans to start the project as he did the NeuStream, about 1/20th of its eventual size. By year two, he’ll start construction on a 100,000 square-foot facility.

And it will pay for itself, he says. But he’ll start with a $10 million grant from the Department of Energy, already applied for, and money from venture capitalists.

“I have people who are very interested in this,” he said. “It’s a way of getting these rare-earth metals, and it’s a way of cleaning up the coal-fired plants.”

The project won’t cost Colorado Springs Utilities a dime, he says. He wants to put the facility at Drake, so the city will reap the benefits of the jobs, sales-and-use taxes and economic development. However, he said it could also be placed at the Ray Nixon Power Plant in El Paso County.

“Or, it could go anywhere in the nation,” he said. “We need a coal-fired power plant, but we could use any one of those.”

Once the facility is started at a small level, the economics work out, he said. Basically, Neumann says the “green chemical process” will extract about $700 worth of rare-earth metals per ton of fly ash. It only costs $250 per ton to extract them.

“So there’s revenue potential there,” he said.

Neumann will make his proposal to the Board of Directors for the Colorado Springs Utilities at its January meeting. He’s hopeful that the board will approve the proposal and he can get started.

But it might not be that easy.

Tim Leigh, a board member and City Councilor, has been a long-time critic of the NeuStream, NSG’s first partnership with CSU. In that project, CSU agreed to pay a total of $121 million for the coal scrubber which will remove sulfur dioxide from coal emissions, helping the power plant reach compliance with federal regulations.

“If he brings $20 million to the table, I’ll listen with an open mind,” Leigh said of the new proposal. “It’s using Utilities as the guarantor that I find reprehensible.”

And Leigh says he won’t support it at Drake, which he thinks should be de-commissioned.

“That’s going to have to go as we have to meet expected federal regulations,” he said.

Leigh has another problem: the timing of Neumann’s announcement.

“I think it would have been better to show the proposal to the board before going to the press,” he said. “But that can be worked out.”

Mayor Steve Bach was among the first leaders who suggested that Drake be de-commissioned and torn down in order to stimulate economic development downtown. He’s urged the board to study the issue.

Sodium Metal Extraction Industrial Methods, Its Properties and Uses

Sodium Metal Extraction Industrial Methods, Its Properties and Uses

Process for the Manufacture
of Sodium Metal

Sodium is a highly reactive metal which a chemical symbol “Na” it placed in 3rd row and 1st column of periodic table in a group of alkali metals, It is identified with its atomic number 11 and atomic mass 22.989.

Where do I find it?

Naturally it is present in common salt called sodium chloride ‘NaCl’ , in chile salt petre NaNO3, cryolite(Na3AlF6) and sodium sesqui carbonate.

Extraction methods:

To extract sodium as it is we have two famous methods

Castner Process: Principle method is Electrolysis of sodium hydroxide

Down’s process: Based on Electrolysis of sodium chloride

Castner process:

By the application of electrolysis technique sodium hydroxide is fused at temperature of 318 oC so that at cathode electrode sodium get deposited and liberating oxygen at anode electrode. Steps of the process:

NaoH ↔ Na+ + OH- , this is fused sodium hydroxide reaction producing individual ions

When the electrical supplying is given sodium ion move toward       Na++ e- → Na

At anode water and oxygen are evolved due to decomposing of OH- as per the reaction,             4OH- →2H2O +O2 +4e-

Above reaction are carried continuously producing sodium collected at receiver, oxygen and hydrogen. Some of the water is evaporated or decomposed to hydrogen and oxygen.

Castner's Process for the Manufacture of Sodium Metal

The electrolytic model explains the process of operation which operates at 318-330 oC by using gas burners. Negative supply is given to solid NaOH filled in iron support and positive to the Nickel anodes the whole set up is fitted in iron pot.  The dimension this iron tank range about 1.5 ft wide and 2 ft high with a capacity of 480 kg of fused NaOH. Nickel gauze separates cathode and anode electrodes and prevents the molten sodium formed at cathode to oxygen liberated at anode. Gas burners are used for start up to raise the temperature to 315 oC as the on the run the temperature is maintained by the reaction between electrode maintain the temperature.  Sodium metal float to the surface collected in receiver provided with mantle at the top at the lid and seal from atmosphere to prevent contact of oxygen. The molten sodium is removed as on when is reaches the level. A prefect seal is maintained with the iron pot and the lid with asbestos rings.

Limitation: sodium is soluble in sodium hydroxide as the temperature rises above 315 oC and separation become inflexible.

Properties of sodium metal:

Physical:

Melting point: 97.5

Boiling point: 883

Sp gravity: 0.97 gm/cc

Conduction: good conductor of electricity

Appearance: silver white

Density compared with water: lighter than water

It can be cut with a knife, because it is soft.

 

Chemical:

Highly reactive

Burns with oxygen forming into sodium monoxide and sodium peroxide.      4Na + O2 →2 Na2O

Liberate hydrogen when reacted with Hydrochloric acid.      2Na +2HCl → 2NaCl +H2

It replaces hydrogen due to high electro positivity.       2Na + 2HNO3 →2NaNO3 +H2

When exposed to open surrounding it reacts with moisture forming Na2O and to NaOH finally to Na2CO3.

2Na + O2 → Na2O2

Na2O +H2O→ 2NaOH

2NaOH + CO2 → Na2CO3 +H2O

Sodium metal Uses:

It is a starting material for production and manufacturing of highly valuable  chemical products like sodium hydroxide, NaCN, sodamide, dyes, perfumes, artificial rubber etc,. It take can be used as reducing agent in the form of sodium amalgam, as a detecting element of nitrogen, sulphur and halogens, deals in the extraction process of boron and silicon

Rare Metal Extraction Program

Rare Metal Extraction Program

Talk about recycling and reinventing! Three hundred eight-six Honda hybrid vehicles stored for sale were made unusable by the March 2011 earthquake that led to a devastating tsunami. But all was not lost. The rare metal from nickel-metal hydride batteries could be extracted and put to new use.

Extracting rare metals from the earth involves mining and the environmental impact the process entails. But reusing them can help curb demand by companies that need them. Japanese automaker Honda is spearheading a process to reuse rare earth metals extracted from nickel metal hydride batteries for new ones in a bid to preserve precious and finite resources.

The initiative has been put in place at the plant of Japan Metals & Chemicals (JMC), where Honda has been extracting an oxide containing rare earth metals from used nickel-metal hydride batteries. Honda has succeeded in extracting metalized rare earth that can be used directly as negative-electrode materials for those batteries.

The good news is that the rare earth metals extracted in this process have a purity of more than 99%, which is as high as that of ordinary traded, newly mined rare earth metals. In addition, the new process enables the extraction of as much as above 80% of rare earth metals contained in nickel-metal hydride battery.

Starting early March, the extracted rare earth metals are being supplied from JMC to a battery manufacturer, which will reuse them as negative-electrode materials for nickel-metal hydride batteries for hybrid vehicles. This first batch came from the vehicles rendered useless by the earthquake.

The plans go further. As soon as a sufficient volume is secured, Honda said it will begin applying the same process and recycle rare earth metals extracted from used nickel-metal hydride batteries collected by Honda dealers through battery replacement.

Honda said it will try to extract rare earth metals not only from nickel-metal hydride batteries but also from various used parts to increase the volume of material being recycled.

WHO IS VERY IMPORTANT MATERIALS

VERY IMPORTANT MATERIALS

The extraction and manufacture of aluminium and sodium are described. The extraction, smelting and purification of copper is covered and similarly notes on the extraction of zinc, titanium and chromium. How to extract a metal is one technological issue, but finally some economic and environmental Issues and metal recycling are discussed as a result of metal extraction. Below is the index of revision notes on extraction procedures and theory, so, scroll down for revision notes on extraction procedures and theory which should prove useful for school/college assignments/projects on ways of extracting metals from their ores.

A vast array of raw materials, including minerals and 'high-tech metals', play a key role in the development of industrial applications and advanced consumer products. According to a recent report by an expert group in the framework of the EU Raw Materials Initiative, Europe is in a vulnerable position when it comes to securing its supply of some of these raw materials: out of 41 minerals and metals analysed, the experts labelled 14 as critical. The results of the report will be used in the drafting of strategies to ensure access to raw materials which the European Commission will present in autumn 2010.
'Critical raw materials for the EU  [2 MB] ' was written by an ad hoc working group, chaired by the European Commission and made up of experts from national ministries, geological surveys and industry. The report was an important step towards achieving the objective of defining critical raw materials, as outlined in the EU's Raw Materials Initiative (see box).

After analysing 41 minerals and metals, the team produced a list of 14 raw materials which they deemed critical to the EU: antimony, beryllium, cobalt, fluorspar, gallium, germanium, graphite, indium, magnesium, niobium, platinum group metals, rare earths, tantalum and tungsten. Forecasts indicate that demand for some of these could more than triple by 2030, compared to 2006 levels.

Demand is increasing for minerals and 'high-tech metals' due to the economic growth of developing countries. The emergence of new technologies and products also drives demand. For example, flat-screen TVs and mobile phones need metals, such as antimony, cobalt, lithium, tantalum and tungsten. Many of the new environmentally friendly products also need these raw materials. Electric cars require lithium and neodymium; car catalysts cannot work without platinum; and solar panels are developed using gallium and indium.

Increasing demands on supply

Risks to reliable supplies to Europe come from fast-growing emerging economies, especially those which are blessed with their own deposits of minerals and metals. Now that a number of these countries are pursuing ambitious industrial development strategies, they are beginning to reserve more and more of these resources for their own use. Government measures, such as export taxes, quotas and subsidies are being used in a way that distorts the trade of raw materials on world markets.

Supply risk issues are compounded by the fact that production of some critical raw materials is often concentrated in a few countries. For instance, China produces more than 90% of the world's rare earths and antimony, about 90% of niobium comes from Brazil, and 77% of platinum comes from South Africa.

The nature of mining for these raw materials also has to be taken into account. They are often produced as by-products through the mining and processing of major metals like copper and zinc, which mainly drive their extraction. This can leave industry facing a crisis of availability, as happened in 2000 when there was a rush for tantalum due to the boom in mobile phone production.

The report also noted that the EU has its own valuable but under-exploited deposits of minerals and metals. However, exploitation and extraction is hampered by competition from other land-use needs, and mining regulations can make the transition from discovery to extraction a slow process.

"We need fair play on external markets, a good framework to foster sustainable raw materials supply from EU sources as well as improved resource efficiency and more use of recycling," said European Commission Vice-President Antonio Tajani, in charge of Industry and Entrepreneurship.

Gauging "criticality"

When considering whether a raw material is critical, the Group assessed two types of risk. Supply risk took account of the political and economic stability of the producing countries, along with levels of production concentration, whether any substitute materials are readily available, and rates of recycling. Similarly, the environmental country risk took account of environmentally related risks.

The report makes a number of policy recommendations to help improve supply of critical raw materials and so minimise the risk of shortages.

More raw data

In addition to updating the critical list every five years, the Group suggests efforts should be made to improve the information that is available on raw materials. It also wants to see more research into the life-cycles of raw materials and the products they are used in.

Access to primary resources will have to improve to ensure supply. In the EU that will require fair treatment of mining and extraction compared with other forms of land use. And more needs to be done to promote sustainable exploration in and outside Europe.

The EU will have to make sure that it keeps a close eye on trade and investment activities which hamper the smooth functioning of international markets for raw materials.

More must be done to improve the efficiency of recycling of raw materials. This means an end to stockpiling at home, dumping in landfills and incineration. Promoting more research on ways to optimise recycling could help bring about positive change.

The Group also recommends that efforts should be made to find substitutes for some of these critical metals and minerals. Research in this area could be promoted under EU framework programmes.

General Principles of Extraction of Metals

The powdered ore is suspended in a stream of water. The heavier ore particles collect behind the riffles and the gangue particles are carried away with the stream of water. Hydraulic classifier is shown in this. Powdered ore is dropped from the top of classifier and strong stream of water is introduced from the bottom. The lighter gangue particles are carried away by the water while the heavier ore particles settle down. Generally, Oxide and carbonate ores are concentrated by this method. For example, tin ore (cassiterite) and iron ore (haematite) are concentrated by gravity method.
Metals occur in nature sometimes free but mostly in combined state. The natural mode of occurrence of a metals is largely dependent on its nature. Those metals which are least reactive and have little or no affinity for oxygen, moisture and other chemical reagents occur in free or metallic or native state i.e., in uncombined state. Most of the metals are reactive and hence are found in combined state i.e., as compounds.
The natural substances in which the metals or their compounds occur in the earth are called minerals. The mineral has a definite composition. It may be a single compound or a complex mixture. The minerals from which the metals can be conveniently and economically extracted are known as ores. All the ores are minerals but all minerals cannot be ores. For example, both bauxite (Al2O3. 2H2O) and clay (Al2O3.2SiO2.2H2O) are minerals of aluminium. It is bauxite which is used for extraction of aluminium and not clay. Thus, bauxite is an ore of aluminium. Ores may be divided into four groups.

Native ores : These ores contain metals in free state, e.g., silver, gold, platinum, mercury, copper, etc. These are found usually associated with rock or alluvial materials like clay, sand, etc. Sometimes lumps of pure metals are also found. These are termed nuggets.

Oxidised ores : In these ores. Metals re present as their oxides or oxysalts such as carbonates, nitrates, sulphates, phosphates, silicates, etc.

Halide ores : Metallic halides are very few in nature. Chlorides are most common.


2. METALLURGY:

The whole process of obtaining a pure metal from one of its ores is known as metallurgy.
In order to extract the metal from ores, several physical and chemical methods are used. The method used depends upon the nature of the ore, the properties of the metal and the local conditions, Thus, it is not possible to have a universal method for the extraction of all the metals from their ores.  However, the metallurgy of a metal involves three main operations:

Concentration or dressing of Ore,

Reduction of Ore

Purification or refining of Ore


Concentration or dressing of ores: Ores usually contain soil, sand, stones and other useless silicates. These undesired impurities present in ores are called Gangue or Matrix. The removal of these impurities from the ores is known as concentration. Before the ore is subjected to concentration, it is crushed into small pieces in gyratory crushers. The crushed ore is then grinded with the help of rollers or in the stamp mill to powder form.


Physical Methods

The following physical methods are generally employed for the concentration of the ores depending upon the nature of the ore.

Gravity separation : The separation is based on the difference in the specific gravities of the gangue particles and the ore particles. The powdered ore is agitated with water or washed with a running stream of water. The heavy ore particles settle down while the lighter particles of sand, clay, etc., are washed away. For this either Wilfley table is used. It a wooden table having slanting floor on which long wooden strips called riffles are fixed.

Types of Extraction Metals

Many metals are found in the Earth's crust as ores. An ore is usually a compound of the metal mixed with impurities. When the metal is dug up, a method must be used to separate the metal from the rest of the ore. This is called extracting the metal.

The method of extraction depends on how reactive the metal is. The more reactive the metal, the more difficult it is to extract from its compound.

Electrolysis

Electrolysis is the most powerful extraction method. But it takes a lot of electricity and that makes it expensive. Hence, electrolysis is only used for the most reactive metals.

Metal: Method of extraction:
Potassium Electrolysis
Sodium Electrolysis
Calcium Electrolysis
Magnesium Electrolysis
Aluminium Electrolysis
Zinc Heat with carbon or carbon monoxide
Iron Heat with carbon or carbon monoxide
Lead Heat with carbon or carbon monoxide
Copper Roasting in air
Silver Occur naturally
Gold Occur naturally
Examples of the different methods of extraction

Electrolysis: Used in extracting aluminium and extracting sodium from rock salt.

In the case of the rock salt, it is first melted in giant steel tanks:



The extraction of aluminium is dealt with in a separate learn its within this topic.

Heating with Carbon monoxide: Used for extracting iron from iron ore using the blast furnace.



Roasting in Air: Used in extractingcopper from copper (I) sulphide (copper pyrites).



The copper is extracted by roasting the ore in air.

Recycling metals

Metals are non-renewable resources. This means once dug up it cannot be replaced. Hence, the supply will eventually run out.

For example: it is expected that tin will run out within the next 15 years and copper in the next 40 years! Therefore,the recycling of these two useful metals and others such as iron and aluminium is most important.

In recycling, metals are melted down before reshaping into their new use. However, this can be costly. Recycling companies will only recycle if it is economical!

Pyrometallurgy

Pyrometallurgy involves high temperature processes where chemical reactions take place among gases, solids, and molten materials. Solids containing valuable metals are reacted to form intermediate compounds for further processing or converted into their elemental or metallic state. Pyrometallurgical processes that involve gases and solids are typified by calcining and roasting operations. Processes that produce molten products are collectively referred to as smelting operations. The energy required to sustain the high temperature pyrometallurgical processes may come entirely from the exothermic nature of the chemical reactions taking place, usually oxidation reactions. Often, however, energy must be added to the process by combustion of fuel or, in the case of some smelting processes, by the direct application of electrical energy.
Ellingham Diagrams are a useful way of analysing the possible reactions, and so predicting their outcome.

Hydrometallurgy

Hydrometallurgy is concerned with processes involving aqueous solutions to extract metals from ores. The most common hydrometallurgical process is leaching, which involves dissolution of the valuable metals into the aqueous solution. After the solution is separated from the ore solids, the solution is often subjected to various processes of purification and concentration before the valuable metal is recovered either in its metallic state or as a chemical compound. The solution purification and concentration processes may include precipitation, distillation, adsorption, and solvent extraction. The final recovery step may involve precipitation, cementation, or an electrometallurgical process. Sometimes, hydrometallurgical processes may be carried out directly on the ore material without any pretreatment steps. More often, the ore must be pretreated by various mineral processing steps, and sometimes by pyrometallurgical processes.

Mineral processing

Mineral processing

Mineral processing involves the processes used to manipulate the particle size of solid raw materials and to separate valuable materials from materials of no value, referred to as gangue. Usually, particle size reduction, also referred to as comminution, is required to permit efficient separation of the valuable materials from gangue. Separation processes take advantage of physical properties of the materials in order to separate them from each other. These physical properties can include density, particle size and shape, electrical and magnetic properties, and surface properties. Since many size reduction and separation processes involve the use of water, solid-liquid separation processes are also a subject of mineral processing.

Extractive metallurgy

Extractive metallurgy is the study of the processes used in the separation and concentration (beneficiation) of raw materials. The field is an applied science, covering all aspects of the physical and chemical processes used to produce mineral-containing and metallic materials, sometimes for direct use as a finished product, but more often in a form that requires further physical processing which is generally the subject of physical metallurgy, ceramics, and other disciplines within the broad field of materials science.
The field of extractive metallurgy encompasses many specialty sub-disciplines, each concerned with various physical and chemical processes that are steps in an overall process of producing a particular material. These specialties are generically grouped into the categories of mineral processing, hydrometallurgy, pyrometallurgy, and electrometallurgy. The distinctions among these groups of sub-disciplines within extractive metallurgy is far from clear, and many commercially important metallurgical processes involve considerable overlap.
The theoretical basis of extractive metallurgy is underpinned by the more general sciences of physics, chemistry, and geology. Additionally, the practice of extractive metallurgy nearly always involves contributions from other scientific fields such as analytical chemistry and mineralogy. Extractive metallurgy is the practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form. In order to convert a metal oxide or sulfide to a purer metal, the ore must be reduced physically, chemically, or electrolytically.
Extractive metallurgists are interested in three primary streams: feed, concentrate (valuable metal oxide/sulfide), and tailings (waste). After mining, large pieces of the ore feed are broken through crushing and/or grinding in order to obtain particles small enough where each particle is either mostly valuable or mostly waste. Concentrating the particles of value in a form supporting separation enables the desired metal to be removed from waste products.
Mining may not be necessary if the ore body and physical environment are conducive to leaching. Leaching dissolves minerals in an ore body and results in an enriched solution. The solution is collected and processed to extract valuable metals.
Ore bodies often contain more than one valuable metal. Tailings of a previous process may be used as a feed in another process to extract a secondary product from the original ore. Additionally, a concentrate may contain more than one valuable metal. That concentrate would then be processed to separate the valuable metals into individual constituents.

Aluminium

Aluminium is very useful metal and used as a lightweight construction material eg greenhouse frames.

Aluminium can be made more resistant to corrosion by a process called anodising.

Aluminium is a reactive metal but it is resistant to corrosion. This is because aluminium reacts in air to form a layer of aluminium oxide which then protects the aluminium from further attack.

This is why it appears to be less reactive than its position in the reactivity series of metals would predict.

For some uses of aluminium it is desirable to increase artificially the thickness of the protective oxide layer in a process is called anodising.

This involves removing the oxide layer by treating the aluminium sheet with sodium hydroxide solution.

The aluminium is then placed in dilute sulphuric acid and is made the positive electrode (anode) used in the electrolysis of the acid.

Oxygen forms on the surface of the aluminium and reacts with the aluminium metal to form a thicker protective oxide layer.

Aluminium can be alloyed to make 'Duralumin' by adding copper (and smaller amounts of magnesium, silicon and iron), to make a stronger alloy used in aircraft components (low density = 'lighter'!), greenhouse and window frames (good anti–corrosion properties), overhead power lines (quite a good conductor and 'light'), but steel strands are included to make the 'line' stronger and poorly electrical conducting ceramic materials are used to insulate the wires from the pylons and the ground.

NOTE on RECYCLING Aluminium

NOTE on RECYCLING Aluminium
About 39% of the aluminium in foil, car components etc. is recycled aluminium.
This makes good economics because recycling saves on costs AND allows a mineral resource like aluminium's bauxite ore to last a lot longer – slower depletion of the Earth's mineral ore resources will make it last longer.
Transport costs may be less (ie within UK now), but much more importantly
mining costs are omitted – energy/machinery involved in digging out the ore, crushing it, transporting the ore,
and the cost of actually extracting the metal from its finite ore resource – electrolysis plant, expensive electrical energy used
So, scrap metal merchants are doing a roaring trade at the moment.
The savings are partly reduced by the cost off collecting waste/scrap metal and purifying for further use.
It is estimated that recycling aluminium only uses 5% of the energy required to extracted the same mass of aluminium from its ore – the original aluminium extraction uses very expensive electrical energy for the electrolysis.

GENERAL NOTE ON ELECTROLYSIS:

GENERAL NOTE ON ELECTROLYSIS:
Any molten or dissolved material in which the liquid contains free moving ions is called the electrolyte.
Ions are charged particles e.g. Na+ sodium ion, or Cl– chloride ion, and their movement or flow constitutes an electric current, because a current is moving charged particles.
What does the complete electrical circuit consist of?
There are two ion currents in the electrolyte flowing in opposite directions:
positive cations e.g. Al3+ attracted to the negative cathode electrode,
and negative anions e.g. O2– attracted to the positive anode electrode,
BUT remember no electrons flow in the electrolyte, only in the graphite or metal wiring!
The circuit of 'charge flow' is completed by the electrons moving around the external circuit e.g. copper wire or graphite electrode, from the positive to the negative electrode
This e– flow from +ve to –ve electrode perhaps doesn't make sense until you look at the electrode reactions, electrons released at the +ve anode move round the external circuit to produce the electron rich negative cathode electrode.
Electron balancing: In the above process it takes the removal of four electrons from two oxide ions to form one oxygen molecule and the gain of three electrons by each aluminium ion to form one aluminium atom.
Therefore for every 12 electrons you get 3 oxygen molecules and 4 aluminium atoms formed.
This means you can do mole ratio product calculations.

The Extraction of Aluminium

The process of electrolysis uses of large amounts of energy in the extraction of a reactive metals and makes aluminium expensive to produce.

Aluminium is a very useful metal but expensive to produce.

Because its position in the reactivity series of metals, aluminium cannot be extracted using carbon because it is above carbon in the reactivity series ie more reactive than carbon in the series, carbon is not reactive enough to displace aluminium from its compounds such as aluminium oxide.
So, if aluminium is too reactive to be obtained by carbon reduction of its oxide another method must be employed which is called electrolysis.
Aluminium is obtained from mining the mineral bauxite which is mainly aluminium oxide (Al2O3) and bauxite must be purified prior to electrolysis, adding to the manufacturing costs.
The purified bauxite ore of aluminium oxide is continuously fed in. Cryolite is added to lower the melting point and dissolve the ore.
The ore–compound containing the aluminium must be molten so the ions are free to move to the electrodes. The conducting melt is called the electrolyte, so extracting aluminium this way involves the electrolysis of molten aluminium oxide.
Ions must be free to move to the electrodes called the cathode (–, negative), attracting positive ions e.g. Al3+, and the anode (+, positive) which attracts negative ions e.g. O2–.
When the d.c. current is passed through aluminium forms at the negative cathode (metal*) and sinks to the bottom of the tank where it can tapped off, collected and run into moulds to cool down before transportation to it will be used to make things.
At the positive anode, oxygen gas is formed (non–metal*). This is quite a problem. At the high temperature of the electrolysis cell it burns and oxidises away the carbon electrodes to form toxic carbon monoxide or carbon dioxide. So the carbon–graphite electrode is regularly replaced and the waste gases dealt with!
It is a costly process (6x more than Fe!) due to the large quantities of expensive electrical energy needed for the process.
* Two general rules:
Metals and hydrogen (from positive ions), form at the negative cathode electrode.
Non–metals (from negative ions), form at the positive anode electrode.
Raw materials for the electrolysis process:

Bauxite ore of impure aluminium oxide [Al2O3 made up of Al3+ and O2– ions]

Carbon (graphite) for the electrodes.

Cryolite reduces the melting point of the ore and saves energy, because the ions must be free to move to carry the current and less energy is needed to melt the aluminium oxide obtained from the bauxite ore.

Electrolysis means using d.c. electrical energy to bring about chemical changes e.g. decomposition of a compound to form metal deposits or release gases. The electrical energy splits the compound!

At the electrolyte connections called the anode electrode (+, attracts – ions) and the cathode electrode (–, attracts + ions). An electrolyte is a conducting melt or solution of freely moving ions which carry the charge of the electric current.

ELECTRODE EQUATIONS: redox details of the electrode processes
Electrolysis reminders – the negative electrode (–) is called the cathode and attracts positive ions or cations e.g. Al3+, and the positive electrode (+) is called the anode and attracts negative ions or anions e.g. O2–.
The negative cathode electrode attracts positive ions, the aluminium ion.
At the negative (–) cathode, reduction occurs (electron gain) when the positive aluminium ions are attracted to it. They gain three electrons to change to neutral Al atoms.
Al3+ + 3e– ==> Al
The positive anode attracts negative ions, the oxide ion.
At the positive (+) anode, oxidation takes place (electron loss) when the negative oxide ions are attracted to it. They lose two electrons forming neutral oxygen molecules.
2O2– ==> O2 + 4e–
or
2O2– – 4e– ==> O2
Note: Reduction and Oxidation always go together!
The overall electrolytic decomposition is ...
aluminium oxide ==> aluminium + oxygen
2Al2O3 ==> 4Al + 3O2
and is a very endothermic process, lots of electrical energy input!
Note that the aluminium oxide loses its oxygen, therefore in this electrolytic process the compound aluminium oxide is reduced to the metal aluminium.

The extraction of aluminium and sodium by electrolysis

The extraction of aluminium and sodium by electrolysis

How do we extract reactive metals that cannot be obtained using carbon? Why do we need to use electrolysis to obtain certain metals from their ores? e.g. how do we extract aluminium from its bauxite ore containing aluminium oxide? How do we extract sodium from salts like sodium chloride? All the electrolytic process are described complete with the electrolysis electrode equations. Scroll down for revision notes on extraction procedures and theory which should prove useful for school/college assignments/projects on ways of extracting metals from their ores.